The formula for calculating the pressure drop for two-phase fluids in pipes is analogous to the equivalent single-phase flow version shown in Eqn (3.19)
, except that the friction factor and physical properties are replaced by their two-phase equivalents:
The pressure loss term in Eqn (3.34)
includes a two-phase friction factor, fM
. In the past, researchers have spent much effort in developing predictive correlations for the two-phase friction factor, as well as the slip liquid holdup term.